Interventional X-ray angiography procedures are generally based on real time, two-dimensional (2D) minimally invasive image guidance of endovascular material through the vasculature or the human vessels. The imaging modality of choice for the interactive tracking of guide wires and catheters is an X-ray angio machine. Typically, interactive tracking of such endovascular material, e.g. a guide wire and/or catheter, have been achieved with an X-ray angiography instrument. Recently introduced three-dimensional rotational angiography (3DRA) techniques have significantly improved upon standard 2D angio imaging techniques by adding a third imaging dimension. A 3DRA imaging allows for a better understanding and assessment of the vessel morphology, as well as the mutual relationship of vessel pathology and surrounding branches.
In many clinical procedures, a diagnostic scan of the relevant anatomical region has already been obtained, e.g. using conventional CT and/or MR technology. Thus, the diagnostic scan information is frequently available for a patient who is undergoing a minimally invasive, interventional treatment. The potential for combining the CT or MR data set with the 3DRA data set, i.e. image fusion, has been investigated. However, to maximise the potential benefit to clinicians and other personnel, image fusion systems should be designed to present two independent data sets in such a way, that the combined image is easy to interpret and manipulate, while offering at the same time a maximum of clinically relevant information.
Prior approaches to image fusion has involved a presentation that combines 2D cross sections of two data sets. This presentation mode is not ideal, because it is impossible for a clinician to interpret the 3D morphology of a vessel from a 2D cross section. For the optimal usage of such combinations it is of importance that all the data encapsulated in the separated data sets are easily accessible, without cluttering the screen with an abundance of data. Further, it is of importance that the spatial relationship between the different data sets is clearly presented.
D. Ruijters et al. describes “Silhouette Fusion of Vascular and Anatomical Volume Data” in International Symposium on Biomedical Imaging (ISBI), pp. 121-124, Washington D.C., USA, April 2006. In this conference paper, a method is described for a combined hybrid visualisation of cerebral blood vessels, segmented from a 3D rotational angiography data set, and data sets containing the soft tissue anatomy, such as CT or MR. The paper describes a combined visualisation of the cerebral blood vessels, segmented from 3DRA data sets and data sets containing the surrounding anatomy, obtained from CT or MR.
Further, U.S. Pat. No. 6,879,711 B2 describes a method for automatic registration of three-dimensional images, wherein the visualisation of the blood vessels can be obtained by the comparison of a three-dimensional digital image obtained by means of a radiology apparatus and a three-dimensional digital image obtained by means of a nuclear magnetic resonance apparatus.